curl_strerror was added in php 5.5, and it appears to be supported in hhvm as well, so I'm really not sure why this is an undefined function.

Because Wikimedia doesn't run php5.5/hhvm everywhere and still has a load of zend php5.3 machines?

So what is wrong with this check in the code: if ( version_compare( PHP_VERSION, '5.5.0' ) >= 0 ) { call it }?

What is PHP_VERSION on production?

In T106579#1472177, @Nikerabbit wrote:

What is PHP_VERSION on production?

One of these:

5.3.10-1ubuntu3.19+wmf1
5.5.9-1ubuntu4.11
5.6.99-hhvm

I'm still confused:

> var_dump( version_compare( '5.6.99-hhvm', '5.5.0' ) );
int(1)

> var_dump( version_compare( '5.5.9-1ubuntu4.11', '5.5.0' ) );
int(1)

> var_dump( version_compare( '5.3.10-1ubuntu3.19+wmf1', '5.5.0' ) );
int(-1)

Which one of the above does not have it?

Change 226348 had a related patch set uploaded (by Nikerabbit):
Use feature test rather than version check

https://gerrit.wikimedia.org/r/226348

Can we just use http://php.net/manual/en/function.function-exists.php ?

In T106579#1472270, @aaron wrote:

Can we just use http://php.net/manual/en/function.function-exists.php ?

Heh, mid air collision :)

Change 226348 merged by Aaron Schulz:
Use feature test rather than version check

https://gerrit.wikimedia.org/r/226348

I'm going to backport this to wmf15

Change 226388 had a related patch set uploaded (by 20after4):
Use feature test rather than version check

https://gerrit.wikimedia.org/r/226388

Change 226388 merged by 20after4:
Use feature test rather than version check

https://gerrit.wikimedia.org/r/226388